The invention relates to an X-ray spectrometer which is arranged in an evacuatable housing and which comprises a wavelength-dependent X-ray detection system and--for irradiating a specimen to be examined--an electron source for generating an electron beam and an X-ray source with an anticathode on which the electron beam can be directed by means of an electrostatic deflection system in order to generate an X-ray beam.
An X-ray spectrometer of this kind is particularly suitable for chemical analysis because the X-radiation generated in the specimen being examined contains characteristic X-radiation which originates from the chemical elements present in the specimen. By wavelength-dependent measurement and analysis of the X-radiation generated, elements emitting characteristic X-radiation can be indentified and quantized by measurement of the intensity of the relevant radiation. For the examination of a specimen containing light elements, such as B, C, Na, Al or Mg, an electron beam is preferably used for irradiation; and for the examination of a specimen containing heavier elements, an X-ray beam is preferably used for irradiation.
French Patent Specification No. 1,558,130 discloses an X-ray spectrometer of the described kind in which the electrostatic deflection device can be used to direct the electron beam onto either the specimen to be examined or onto the anticathode which is in this case situated opposite the specimen.
It is a drawback of the described known X-ray spectrometer that, in order to irradiate the specimen by means of X-rays, electrons supplied by the electron source must first be accelerated, after which the accelerated electrons are deflected onto the anticathode. One of the two voltage sources required for this purpose is used for the deflection of accelerated electrons, which requires comparatively large electric fields and hence comparatively high electric voltages.